"Believe it or not, Kat isn't at home, please leave a message at the beep. She must be out or she'd pick up the phone. Where could she be? Believe it or not, Kat's not home!"

Thursday night's episode of The Late Late Show revealed that Kat Dennings' voicemail greeting — for the past five or six years — is a recording of Jason Alexander'sSeinfeld character.

"I had to record it off YouTube because I couldn't find an actual song of it, but it's George Costanza's voicemail on my voicemail," the 2 Broke Girls actress said, confirming that the greeting never actually says her own name. "So when people leave a message, they're like, 'Uh, I guess this is you?'"

Alexander then recorded live a version of the "Greatest American Hero" song that does actually identify her: "Believe it or not, Kat isn't at home, please leave a message at the beep. She must be out or she'd pick up the phone. Where could she be? Believe it or not, Kat's not home."